Rapid recycling of spent lithium-ion batteries using microwave route

Abstract

The discarded lithium-ion batteries containing valuable metals and graphite are excellent resources in the context of urban mining. In the present study, electrode sheets of mixed spent lithium-ion batteries were crushed, sieved, followed by froth flotation for physical separation of graphite values. The current study investigates the carbothermal reduction of the active cathode material in a microwave furnace under ambient conditions using recovered graphite. The microwave response of "as such" active material (mixed anode and cathode), and "separated" active cathode material at 800W, 2.5GHz, was compared. The magnetic product at the optimum condition (850°C, 30 % C, 10min) consists of 73 % Co, 13 % Mn, 6 % Ni, 8 % O and saturation magnetization of 108emu/g, and lithium extraction rate: 93 %. Higher recovery of metal and graphite values are obtained by processing of "separated" cathode material compared to "as such" active materials. The effect of microwave treatment was found successful for metal dissolution in the hydrometallurgical route also. The average activation energy is 72 and 94kJ/mol for "separated" and "as such" active materials, respectively. The cost calculations show that the process is economical.